Does anyone have any information on this? A simple google search didnt turn up a lot of useful information but something I read described it as follows:

One of the most significant causes for concern around the TPPA is that it would give foreign investors the right to sue the New Zealand government in private offshore tribunals for introducing laws or policies which they claim would significantly hurt their investments. This is called Investor-State Dispute Settlement (ISDS)

I assume the same applies to other countries who sign agreements involving an ISDS.